You may be trying to re-invent the wheel, because the ski industry already has "AT" or Alpine Touring boots. These are like downhill ski boots, but lighter, and with Vibram soles to help in climbing rock. Yes, they do accept crampons. Personally, I own a pair of Scarpa Denali AT boots, which are 4-buckle, fairly heavy, but very supportive on the downhills. I also own a pair of Scarpa F1 AT boots, which have a bellows on the toes, so you can walk and flat-ski more naturally, and are close to the lightest, if not the lightest, AT boots on the market. The trade-off is that they are not as supportive on the downhill portions.